The Animal Core will provide pedigreed rats from inbred colonies of normotensive WKY and of hypertensive SHRSP rats. During the next funding period a major function of this core will be to carry out cross breeding programs to determine whether specific traits, that we have found to be confined to the SHRSP strain, segregate genetically in F2 and back-cross generations with blood pressure elevation. Testing for such a cosegregation will give insight into the possible causal relationship between the specific trait and hypertension.